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Thread: Tohatsu / mercury 3 cyl water on plugs.

  1. #21
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    On removing broken studs/ bolts with Vise Grips, don't try to just unscrew the stud: take your time and wiggle it back and forth, getting it looser and looser before trying to unscrew it. That method has worked for me where I couldn't use the old "hot wrench" on the block (such as in the bilge of an inboard).

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

  2. #22
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    Vise grips and lots of heat around the bolt area, but not the bolt. When they move go back and forth and a little at a time. That seems to work the best for me. I hate easy outs because when they break off your screwed. Hardened steel is impossible to drill out by hand when surrounded by soft aluminum. 103 PSI seems to be on the low side?

  3. #23
    Team Member ice_spy's Avatar
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    Well got them all out bar one. Took to the machinist to remove the last bolt as it snapped off flush. Heat and vise grips worked a treat.

    Assembled the motor today.
    Bad news. Water still on plugs, bottom cyclinder the worst.
    So far I have skimmed the head , the block.
    Replaced the exhaust plate gasket and the powerhead base gasket. All surfaces clean and flat. No scratches or pitting. Head looks perfect, no cracks although not pressure tested.
    All bolts were torqued to spec and re torqued after 10 mins running.

    I GIVE UP ! Spent $400 and still nowhere. Can't understand where it could be leaking in still. The only thing I can think of is I'm using non genuine gaskets and perhaps the head gasket has failed.
    Well that's it for me. Can't afford a new engine.
    Feeling dissapointed is an understatement.
    The race never stops

  4. #24
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    Quote Originally Posted by ice_spy View Post
    Well got them all out bar one. Took to the machinist to remove the last bolt as it snapped off flush. Heat and vise grips worked a treat.

    Assembled the motor today.
    Bad news. Water still on plugs, bottom cyclinder the worst.
    So far I have skimmed the head , the block.
    Replaced the exhaust plate gasket and the powerhead base gasket. All surfaces clean and flat. No scratches or pitting. Head looks perfect, no cracks although not pressure tested.
    All bolts were torqued to spec and re torqued after 10 mins running.

    I GIVE UP ! Spent $400 and still nowhere. Can't understand where it could be leaking in still. The only thing I can think of is I'm using non genuine gaskets and perhaps the head gasket has failed.
    Well that's it for me. Can't afford a new engine.
    Feeling dissapointed is an understatement.
    Try replacing the bottom Crankshaft seal and check the adaptor plate and base gasket. If the adapter plate and base gasket are bad, then water can enter and be stored under the crankshaft end cap and if you have a bad crankcase bottom seal be sucked up affect the bottom cylinder.

    Stephen

  5. #25
    Team Member ice_spy's Avatar
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    Thanks Stephen. It so hard to give advice when you can't see it or know much about what's going on. Appreciate the help.
    The base gasket is brand new. The adapter plate every time I pulled it off (the powerhead) had no water sitting. The crank case bottom seal is around the drive shaft that is separate to any water ports. It is free to air so to speak. I'm beginning to think it is cheap head gaskets that I'm using. The bottom worst due to gravity maybe. I've pulled the head off so many times now, I have to eliminate the chance of it being due to cheap inferior gaskets. At least all bolts free and easy to remove now, it's no big problem to remove the head.
    I asked a marine workshop and they said they would recommend original head gasket before anything else.
    With compression down which seemed strange, and another test showing bottom cylinder is the lowest psi reading, perhaps it's simply blowing the head gasket now I've had the deck milled , the piston height / squish might be too much for the cheap gaskets. If I take it to a shop the 1st thing they will do is put a genuine head gasket on anyways I suppose. I can save money trying this at least.
    I do have new seals but I think this will require to bust the crank halves? And another new base gasket.

    Well so much for " I give up". I'm more like " He who endures, conquers ". Lol.
    The race never stops

  6. #26
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    Zoom in on #3 on the head gasket you posted a pic of.... The gasket is leaking whether you had the block and head skimmed or not... (dark spot on the gasket ring at edge of cylinder) You need to have the surfaces re-checked and if possible not by the shop that did it.... This is also why compression is low. I would also go up on torque to 25-30lb. If it is like my yamaha you cant get a torque wrench to the 2 bottom bolts so you have to do them by hand. Are you sure you are clamping down tight enough on the bolts?

  7. #27
    Team Member ice_spy's Avatar
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    Thanks Dragracer, yes I remove the powerhead to reach the bottom two bolts. Perhaps your right and I need to torque them up to at least 20-23 lb. I think 25 to 30 could be too much.I lightly sanded the head and the engine deck with some 1000grit and flat surface before last rebuild to make sure the slight machine marks were not affecting a blow out on the head gasket.
    I'm leaning towards the head gasket the reason for failure so I have one more spare aftermarket head gasket to test with higher lb. before I go buy a genuine one. Is there an up and down surface for the gasket? Like car engine head gaskets? There is no marks on the gasket.
    The race never stops

  8. #28
    Team Member ice_spy's Avatar
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    Sorry missed the replys on last page. Zul8tr , TCW3 oil Castrol brand and premium 95 octain. 50:1 with a slight drop more for a little more lube.
    Dragracer checking my photos again to look for the leak. Thank you guys. Will let u know how I go.
    The race never stops

  9. #29
    Team Member ice_spy's Avatar
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    Looking at the pics again, notice how bad the misalignment of the gasket is on the bottom piston. This could be causing the failure too as it seems to be most misaligned on cyclinder #3. Lower edge. Could be these cheapo gaskets. They do look rather thin to me on the sealing ring and very wide. Ok here goes attempt # 4.
    The race never stops

  10. #30
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    You should also check the reed valves, a broke one could also cause same problem , cheers lee

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